4 link issues and improvements?

[Just 1 More]

Has anyone replaced the solid bushing ends with a spherical joint? RideTech makes the "R-Joint" which frees up the bind found on typical 4 links. My 68 Camaro has the Ridetech R-joints on every 4 link end and the articulation is night and day better than the poly bushings. I don't have the 33 with the 4 link to put my hands on just yet but I would have to think that replacing the poly bushing ends with the "R-Joints" would really make a huge difference. Here's a video of the comparison. Like I said, I have the R-joint complete 4 link set up on my 68 Camaro and it handles incredible. The R-Joint 4 link is used in a lot of the Optima Auto-X cars as well.
What's y'alls thoughts? https://www.youtube.com/watch?v=GGUUR_3YlQs

[Just 1 More]

Found a picture of the uppers with the R-Joints
174718

[TxMike64]

Be aware that the suspensions in all the FFR kits are Foxbody Mustang based. Those in-the-know in the Mustang community will tell you that the best upper control arms are the Ford stamped steel links (UCAs) paired with good delrin or heim joint (also called rose joints) tubular lower control arms (LCAs). The theory is that because the lower links are not parallel, as you travel though the range of articulation the upper links need to twist and slightly elongate. The large rubber bushings and the open box section of the stamped UCAs can absorb that motion while not tearing/cracking the unibody. See Maximum Motorsports (https://www.maximummotorsports.com/Rear-Upper-Control-Arms-1979-2004-Mustang-P544.aspx)

This is the main reason Ford switched to the 3-link and FFR has followed suit. In the Mustang community it all depends on the intended use: Drag, Road Course, or Street. The recommendations for rear control arm selection with vary WIDELY based on intended use. I would venture to say that Fox-based Mustang suspension is one of the biggest aftermarkets in existence and there are numerous versions of UCA and LCA made by numerous manufacturers. Peruse LMR or CJPonyParts just to get a taste.

I'm sure there are Roadster guys here on the forums that can share what has worked for them on the track. I would venture to guess that the rigidity of the FFR tubular chassis compounds the issue, and rigid control arms might introduce a LOT of bind. My Foxbody had tubular UCAs on it when I bought it and it was terrible. Just by replacing the UCAs the ride quality and tendency to snap-oversteer improved tremendously.

I was going to buy my '33 kit with the 4-link and use stamped steel UCAs and J&M tubular LCAs. Alas I bought a kit second-hand and got the '15 IRS so it's a moot point for me. But this is still my recommendation based off my Mustang experience.

[GoDadGo]

We installed these on my pal's 33 HR and he's much happier with them over the stock uppers.
Pinion angle adjustment was greatly improved as was the ride comfort.

https://www.summitracing.com/parts/qa1-5255/make/ford/model/mustang/year/2000

[TxMike64]

Fraction of the price, just as high quality:

https://steinjager.com/shop/1979-1998-Control-Arms-Rear-Upper-and-Lower-Double-Adjustable-Chrome-Moly-DOM-J0030515

[Just 1 More]

Fraction of the price, just as high quality:

https://steinjager.com/shop/1979-1998-Control-Arms-Rear-Upper-and-Lower-Double-Adjustable-Chrome-Moly-DOM-J0030515

Those look great although I would have to question if the joints have the same sleeving aka: "delrin composite cage" that the R-joints have which help reduce road noise and vibration through the frame/chassis like a solid heim joint is known to do.

[TxMike64]

Yeah, the Steinjagers are pretty noisy. I like the J&Ms that I put on my Foxbody:

https://lmr.com/item/LRS-7998CAK/79-98-mustang-rear-control-arm-kit-j-m-7998cak

[GoDadGo]

Here is a set that may also interest you from Spohn.

https://www.spohn.net/shop/Factory-Five-Racing-MK3-MK4-Roadster/Adjustable-Rear-Upper-Control-Arms-with-Del-Sphere-Pivot-Joints.html

I've got a custom pair of fixed lowers on my MK-4.

[HVACMAN]

i used a set from Dan Ruth. One of the problems with the Gen1 is, the rear wheels were not centered in the wheel well. These addressed that problem.

174945174947